Control-dependent lifetime comparison of igbt module used in propulsion system of urban railway vehicle

This paper performs a lifetime comparison of an IGBT module used in the propulsion system of urban railway vehicles depending on the control schemes of the inverter driving the induction motors. Two control schemes are considered in this paper. The high efficiency control scheme, the first one, extends the output voltage of the inverter to the maximum value of the six-step modulation; therefore, it can reduce the motor currents, which results in small power loss of the inverter. The other scheme is a low torque ripple control scheme. It generates the output voltage of the inverter in the linear modulation range. Depending on the control scheme, the junction temperature of the IGBT during urban railway vehicle operation is estimated based on the power loss and thermal model of the IGBT module. Two temperature profiles are applied to the lifetime model of the IGBT module; then, the lifetimes of the IGBT module under the operation conditions of urban railway system are estimated and compared.